Can I paint one wall?

[Dermot Dempsey]

Yes. If you try to use the material painter tool, it will paint the whole room by default. Instead, you need to open the Wall Specification dialog, go to the Material panel, and change the interior surface material manually. If you already painted the entire room, you may need to open up the Room Specification dialog and set the wall material back to "use default". You may also need to add wall breaks if your wall spans multiple rooms.